Diodes are used in technology for various purposes: rectification, detection, decoupling, etc. They differ from each other in a number of parameters. The selection of a diode should be carried out depending on the requirements for them.
Instructions
Step 1
Regardless of which operation the diode will be used for, when choosing it, be sure to take into account such basic parameters as the maximum allowable forward current and reverse voltage. If the impulse value of the forward current is much higher than the average, take it into account, especially if the diode is semiconductor.
Step 2
If it is necessary to rectify currents of significant frequency, also take into account the speed of the diode. Point semiconductor diodes have a lower intrinsic capacitance than planar diodes, and therefore rectify currents of significant frequency. But they are very weak. Schottky diodes have the same property, at much higher powers.
Step 3
Choose the correct physical principle of the rectifier operation. If the diode requires complete absence of reverse current, but efficiency is not important, use an electric vacuum diode. It is good because it begins to straighten at a low voltage value.
Step 4
The cuprox rectifier also opens at low voltage, but has a very large reverse current, is low-power, and its speed is relatively low. Use it to rectify low frequency AC voltages before measurement.
Step 5
The germanium diode opens at a slightly higher voltage, but it also has less reverse current. Use it, in particular, in detectors of amplitude modulated signals.
Step 6
A selenium rectifier has a high opening voltage and a small allowable reverse voltage, therefore, to rectify significant voltages, they are connected in series. A noticeable reverse current makes it possible to eliminate the equalizing resistors. Such rectifiers can withstand short-term short circuits, but with long-term operation fail for no apparent reason. Use such devices only in cases when they cannot be replaced by any other diodes.
Step 7
Silicon diodes are the most common today. They have almost supplanted other types of rectifiers. Among them, you can choose a device with almost any required parameters. Try to use them whenever possible.
Step 8
Having decided on the requirements for the diode, find a device suitable for all parameters in the reference book.
